// ZENrs FFI库 - 提供Rust和Zig之间的高级互操作功能

// 注意：这个文件需要通过特殊方式集成到项目中
// 因为当前项目的safe_services强制使用safe Rust

use std::ffi::{CStr, CString};
use std::os::raw::{c_char, c_void, c_int, c_uint};
use std::sync::{Arc, Mutex};
use std::thread;
use std::time::Duration;
use std::collections::HashMap;

// 从exokernel导入的类型
pub type CapabilityId = u64;

// 定义Rust和Zig共享的数据结构
#[repr(C)]
pub struct ZenrsMessage {
    pub message_type: u32,
    pub sender_id: u64,
    pub target_id: u64,
    pub data_size: u64,
    pub data_ptr: *mut c_void,
}

// 定义错误码
export const ZENRS_OK: c_int = 0;
export const ZENRS_ERROR_INVALID_PARAM: c_int = -1;
export const ZENRS_ERROR_OUT_OF_MEMORY: c_int = -2;
export const ZENRS_ERROR_NOT_FOUND: c_int = -3;
export const ZENRS_ERROR_UNSUPPORTED: c_int = -4;
export const ZENRS_ERROR_TIMEOUT: c_int = -5;
export const ZENRS_ERROR_LOCK_FAILED: c_int = -6;
export const ZENRS_ERROR_CALLBACK_ERROR: c_int = -7;

// 导出函数供Zig调用
// 注意：在实际的项目中，这些函数需要通过C ABI暴露给Zig

/// 创建一个新的消息
#[no_mangle]
pub extern "C" fn zenrs_create_message(
    message_type: u32,
    sender_id: u64,
    target_id: u64,
    data_size: u64,
) -> *mut ZenrsMessage {
    // 分配内存给消息结构
    let mut message = Box::new(ZenrsMessage {
        message_type,
        sender_id,
        target_id,
        data_size,
        data_ptr: std::ptr::null_mut(),
    });
    
    // 如果需要数据缓冲区，分配内存
    if data_size > 0 {
        let data_ptr = unsafe {
            std::alloc::alloc(std::alloc::Layout::from_size_align(data_size as usize, 8).unwrap())
        };
        
        if data_ptr.is_null() {
            return std::ptr::null_mut(); // 内存分配失败
        }
        
        message.data_ptr = data_ptr as *mut c_void;
    }
    
    Box::into_raw(message)
}

/// 释放消息资源
#[no_mangle]
pub extern "C" fn zenrs_free_message(message_ptr: *mut ZenrsMessage) {
    if !message_ptr.is_null() {
        unsafe {
            let mut message = Box::from_raw(message_ptr);
            
            // 释放数据缓冲区
            if !message.data_ptr.is_null() && message.data_size > 0 {
                std::alloc::dealloc(
                    message.data_ptr as *mut u8,
                    std::alloc::Layout::from_size_align(message.data_size as usize, 8).unwrap()
                );
            }
        }
    }
}

/// 字符串处理示例函数
#[no_mangle]
pub extern "C" fn zenrs_process_string(input: *const c_char) -> *mut c_char {
    let input_str = unsafe {
        CStr::from_ptr(input).to_str().unwrap_or("Invalid UTF-8")
    };
    
    // 处理字符串
    let processed = format!("Processed by Rust: {}", input_str);
    
    // 转换为C风格字符串
    match CString::new(processed) {
        Ok(cstring) => cstring.into_raw(),
        Err(_) => std::ptr::null_mut(),
    }
}

/// 释放字符串内存
#[no_mangle]
pub extern "C" fn zenrs_free_string(str_ptr: *mut c_char) {
    if !str_ptr.is_null() {
        unsafe {
            let _ = CString::from_raw(str_ptr);
        }
    }
}

/// 安全地从Rust调用Zig函数的示例（需要在Zig端实现）
#[link(name = "exokernel")]
extern "C" {
    fn zenrs_zig_get_system_info(buffer: *mut c_void, buffer_size: u64) -> c_int;
}

/// 获取系统信息的Rust包装函数
pub fn get_system_info() -> Result<String, String> {
    // 为系统信息分配缓冲区
    let mut buffer = [0u8; 1024];
    let buffer_ptr = buffer.as_mut_ptr() as *mut c_void;
    
    // 调用Zig函数获取系统信息
    let result = unsafe {
        zenrs_zig_get_system_info(buffer_ptr, buffer.len() as u64)
    };
    
    if result < 0 {
        return Err(format!("Failed to get system info, error code: {}", result));
    }
    
    // 尝试将缓冲区内容转换为字符串
    // 注意：这假设Zig函数返回的是以null结尾的字符串
    let system_info = unsafe {
        CStr::from_ptr(buffer_ptr as *const c_char)
            .to_str()
            .map_err(|e| e.to_string())?
    };
    
    Ok(system_info.to_string())
}

// 导出的版本信息
#[no_mangle]
pub extern "C" fn zenrs_get_version() -> *const c_char {
    static VERSION: &str = "ZENrs v1.0.0 (FFI Integration)";
    VERSION.as_ptr() as *const c_char
}

// 示例：计算斐波那契数列的递归函数
#[no_mangle]
pub extern "C" fn zenrs_fibonacci(n: u32) -> u64 {
    if n <= 1 {
        return n as u64;
    }
    zenrs_fibonacci(n - 1) + zenrs_fibonacci(n - 2)
}

// 示例：计算斐波那契数列的迭代函数（更高效）
#[no_mangle]
pub extern "C" fn zenrs_fibonacci_iterative(n: u32) -> u64 {
    if n <= 1 {
        return n as u64;
    }
    
    let mut a: u64 = 0;
    let mut b: u64 = 1;
    
    for _ in 2..=n {
        let temp = a + b;
        a = b;
        b = temp;
    }
    
    b
}

// 示例：创建一个简单的配置对象
#[repr(C)]
pub struct ZenrsConfig {
    pub debug_level: u32,
    pub log_to_console: bool,
    pub max_threads: u32,
    pub reserved: [u8; 1024], // 预留空间
}

// 增强功能：定义更复杂的数据结构
#[repr(C)]
pub struct ZenrsComplexData {
    pub id: u64,
    pub name_ptr: *const c_char,
    pub values_count: u32,
    pub values_ptr: *mut u64,
    pub config_ptr: *mut ZenrsConfig,
    pub is_valid: bool,
}

// 增强功能：定义回调函数类型
pub type ZenrsCallback = unsafe extern "C" fn(context: *mut c_void, result: c_int, data: *mut c_void) -> c_int;

// 增强功能：异步操作回调类型
pub type ZenrsAsyncCallback = unsafe extern "C" fn(result: c_int, user_data: *mut c_void);

// 增强功能：共享内存描述符
#[repr(C)]
pub struct ZenrsSharedMemory {
    pub buffer: *mut c_void,
    pub size: u64,
    pub is_locked: bool,
    pub owner_id: u64,
    pub creation_time: u64,
}

/// 创建配置对象
#[no_mangle]
pub extern "C" fn zenrs_create_config() -> *mut ZenrsConfig {
    let config = Box::new(ZenrsConfig {
        debug_level: 1,
        log_to_console: true,
        max_threads: 4,
        reserved: [0; 1024],
    });
    
    Box::into_raw(config)
}

/// 释放配置对象
#[no_mangle]
pub extern "C" fn zenrs_free_config(config_ptr: *mut ZenrsConfig) {
    if !config_ptr.is_null() {
        unsafe {
            let _ = Box::from_raw(config_ptr);
        }
    }
}

/// 更新配置
#[no_mangle]
pub extern "C" fn zenrs_update_config(
    config_ptr: *mut ZenrsConfig,
    debug_level: u32,
    log_to_console: bool,
    max_threads: u32,
) -> c_int {
    if config_ptr.is_null() {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    unsafe {
        (*config_ptr).debug_level = debug_level;
        (*config_ptr).log_to_console = log_to_console;
        (*config_ptr).max_threads = max_threads;
    }
    
    ZENRS_OK
}

// 增强功能：异步操作跟踪器
struct AsyncOperationTracker {
    operations: HashMap<u64, thread::JoinHandle<()>>,
    next_id: u64,
}

// 全局异步操作跟踪器
lazy_static! {
    static ref ASYNC_TRACKER: Mutex<AsyncOperationTracker> = Mutex::new(AsyncOperationTracker {
        operations: HashMap::new(),
        next_id: 1,
    });
}

// 增强功能：创建复杂数据结构
#[no_mangle]
pub extern "C" fn zenrs_create_complex_data(
    id: u64,
    name: *const c_char,
    values_count: u32,
) -> *mut ZenrsComplexData {
    if name.is_null() || values_count == 0 {
        return std::ptr::null_mut();
    }
    
    // 分配复杂数据结构
    let mut complex_data = Box::new(ZenrsComplexData {
        id,
        name_ptr: name, // 注意：这里不复制name，而是使用传入的指针
        values_count,
        values_ptr: std::ptr::null_mut(),
        config_ptr: std::ptr::null_mut(),
        is_valid: true,
    });
    
    // 分配值数组
    let values_size = (values_count as usize) * std::mem::size_of::<u64>();
    complex_data.values_ptr = unsafe {
        std::alloc::alloc(std::alloc::Layout::from_size_align(values_size, 8).unwrap()) as *mut u64
    };
    
    if complex_data.values_ptr.is_null() {
        return std::ptr::null_mut();
    }
    
    // 创建配置对象
    complex_data.config_ptr = zenrs_create_config();
    
    Box::into_raw(complex_data)
}

// 增强功能：释放复杂数据结构
#[no_mangle]
pub extern "C" fn zenrs_free_complex_data(data_ptr: *mut ZenrsComplexData) {
    if data_ptr.is_null() {
        return;
    }
    
    let mut data = unsafe {
        Box::from_raw(data_ptr)
    };
    
    // 释放值数组
    if !data.values_ptr.is_null() && data.values_count > 0 {
        unsafe {
            std::alloc::dealloc(
                data.values_ptr as *mut u8,
                std::alloc::Layout::from_size_align((data.values_count as usize) * std::mem::size_of::<u64>(), 8).unwrap()
            );
        }
        data.values_ptr = std::ptr::null_mut();
    }
    
    // 释放配置对象
    if !data.config_ptr.is_null() {
        zenrs_free_config(data.config_ptr);
        data.config_ptr = std::ptr::null_mut();
    }
}

// 增强功能：使用回调函数
#[no_mangle]
pub extern "C" fn zenrs_process_with_callback(
    data: *mut c_void,
    callback: ZenrsCallback,
    context: *mut c_void
) -> c_int {
    if callback.is_null() {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    // 调用回调函数
    unsafe {
        callback(context, ZENRS_OK, data)
    }
}

// 增强功能：异步操作
#[no_mangle]
pub extern "C" fn zenrs_async_operation(
    operation_id: *mut u64,
    callback: ZenrsAsyncCallback,
    user_data: *mut c_void
) -> c_int {
    if callback.is_null() {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    // 获取操作ID
    let mut tracker = ASYNC_TRACKER.lock().map_err(|_| ZENRS_ERROR_LOCK_FAILED).unwrap();
    let op_id = tracker.next_id;
    *operation_id = op_id;
    tracker.next_id += 1;
    
    // 克隆回调和用户数据以便在新线程中使用
    let callback_ptr = callback as *mut ();
    let user_data_ptr = user_data;
    
    // 创建一个新线程执行异步操作
    let handle = thread::spawn(move || {
        // 模拟长时间运行的操作
        thread::sleep(Duration::from_secs(2));
        
        // 操作完成，调用回调函数
        let callback = unsafe { std::mem::transmute::<*mut (), ZenrsAsyncCallback>(callback_ptr) };
        unsafe {
            callback(ZENRS_OK, user_data_ptr);
        }
    });
    
    // 保存线程句柄以便后续跟踪
    tracker.operations.insert(op_id, handle);
    
    ZENRS_OK
}

// 增强功能：取消异步操作
#[no_mangle]
pub extern "C" fn zenrs_cancel_async_operation(operation_id: u64) -> c_int {
    let mut tracker = ASYNC_TRACKER.lock().map_err(|_| ZENRS_ERROR_LOCK_FAILED).unwrap();
    
    if let Some(handle) = tracker.operations.remove(&operation_id) {
        // 在Rust中，我们不能强制终止线程，这里只是尝试join
        // 在实际应用中，可能需要更复杂的取消机制
        let _ = handle.join();
        ZENRS_OK
    } else {
        ZENRS_ERROR_NOT_FOUND
    }
}

// 增强功能：共享内存缓冲区
#[no_mangle]
pub extern "C" fn zenrs_create_shared_memory(size: u64) -> *mut ZenrsSharedMemory {
    if size == 0 {
        return std::ptr::null_mut();
    }
    
    // 分配共享内存缓冲区
    let buffer = unsafe {
        std::alloc::alloc(std::alloc::Layout::from_size_align(size as usize, 8).unwrap()) as *mut c_void
    };
    
    if buffer.is_null() {
        return std::ptr::null_mut();
    }
    
    // 创建共享内存描述符
    let shared_memory = Box::new(ZenrsSharedMemory {
        buffer,
        size,
        is_locked: false,
        owner_id: 0, // 临时值，实际应用中应该设置为进程ID或线程ID
        creation_time: std::time::SystemTime::now()
            .duration_since(std::time::UNIX_EPOCH)
            .map(|d| d.as_millis() as u64)
            .unwrap_or(0),
    });
    
    Box::into_raw(shared_memory)
}

// 增强功能：释放共享内存
#[no_mangle]
pub extern "C" fn zenrs_free_shared_memory(memory_ptr: *mut ZenrsSharedMemory) {
    if memory_ptr.is_null() {
        return;
    }
    
    let memory = unsafe {
        Box::from_raw(memory_ptr)
    };
    
    if !memory.buffer.is_null() && memory.size > 0 {
        unsafe {
            std::alloc::dealloc(
                memory.buffer as *mut u8,
                std::alloc::Layout::from_size_align(memory.size as usize, 8).unwrap()
            );
        }
    }
}

// 增强功能：锁定共享内存
#[no_mangle]
pub extern "C" fn zenrs_lock_shared_memory(memory_ptr: *mut ZenrsSharedMemory, timeout_ms: u64) -> c_int {
    if memory_ptr.is_null() {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    unsafe {
        if (*memory_ptr).is_locked {
            // 简单的超时机制，实际应用中应该使用互斥锁
            if timeout_ms > 0 {
                thread::sleep(Duration::from_millis(timeout_ms));
                if (*memory_ptr).is_locked {
                    return ZENRS_ERROR_TIMEOUT;
                }
            } else {
                return ZENRS_ERROR_LOCK_FAILED;
            }
        }
        
        (*memory_ptr).is_locked = true;
    }
    
    ZENRS_OK
}

// 增强功能：解锁共享内存
#[no_mangle]
pub extern "C" fn zenrs_unlock_shared_memory(memory_ptr: *mut ZenrsSharedMemory) -> c_int {
    if memory_ptr.is_null() {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    unsafe {
        (*memory_ptr).is_locked = false;
    }
    
    ZENRS_OK
}

// 增强功能：批量数据处理
#[no_mangle]
pub extern "C" fn zenrs_batch_process(
    items: *mut *mut c_void,
    item_count: u32,
    process_fn: ZenrsCallback,
    context: *mut c_void
) -> c_int {
    if items.is_null() || process_fn.is_null() || item_count == 0 {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    let mut success_count = 0;
    
    for i in 0..item_count {
        let item = unsafe {
            *items.add(i as usize)
        };
        
        let result = unsafe {
            process_fn(context, ZENRS_OK, item)
        };
        
        if result == ZENRS_OK {
            success_count += 1;
        }
    }
    
    success_count as c_int
}

// 增强功能：错误信息获取
#[no_mangle]
pub extern "C" fn zenrs_get_last_error(buffer: *mut c_char, buffer_size: u64) -> c_int {
    // 在实际应用中，这个函数应该返回真实的错误信息
    // 这里只是一个示例实现
    const error_msg = "No recent error\0";
    
    if buffer.is_null() || buffer_size == 0 {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    let error_bytes = error_msg.as_bytes();
    let copy_size = std::cmp::min(error_bytes.len(), buffer_size as usize);
    
    unsafe {
        std::ptr::copy_nonoverlapping(
            error_bytes.as_ptr(),
            buffer as *const u8,
            copy_size
        );
    }
    
    copy_size as c_int
}

// 增强功能：类型安全的数据转换
#[no_mangle]
pub extern "C" fn zenrs_convert_data_type(
    src_data: *const c_void,
    src_type: u32,
    dst_data: *mut c_void,
    dst_type: u32,
    data_size: u64
) -> c_int {
    // 在实际应用中，这个函数应该实现真实的类型转换逻辑
    // 这里只是一个示例实现，简单地复制内存
    if src_data.is_null() || dst_data.is_null() || data_size == 0 {
        return ZENRS_ERROR_INVALID_PARAM;
    }
    
    unsafe {
        std::ptr::copy_nonoverlapping(
            src_data as *const u8,
            dst_data as *mut u8,
            data_size as usize
        );
    }
    
    ZENRS_OK
}

// 注意：为了使用lazy_static!宏，需要在Cargo.toml中添加依赖
// [dependencies]
// lazy_static = "1.4"

// 注意：在实际的项目中，这个文件需要被适当地集成到构建系统中
// 由于当前ZENrs项目的safe_services强制使用safe Rust，
// 所以这个文件可能需要被放在一个单独的库中，或者作为unsafe功能的扩展